Package structure having MEMS element

Abstract

A package structure having at least an MEMS element is provided, including a chip having electrical connecting pads and the MEMS element; a lid disposed on the chip to cover the MEMS element and having a metal layer provided thereon; first sub-bonding wires electrically connecting to the electrical connecting pads; second sub-bonding wires electrically connecting to the metal layer; an encapsulant disposed on the chip, wherein the top ends of the first and second sub-bonding wires are exposed from the encapsulant; and metallic traces disposed on the encapsulant and electrically connecting to the first sub-bonding wires. The package structure advantageously features reduced size, relatively low costs, diverse bump locations, and an enhanced EMI shielding effect.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to package structures, and more particularly, to a package structure having at least a Micro Electro Mechanical System (MEMS) element.[0003]2. Description of Related Art[0004]Micro Electro Mechanical System (MEMS) techniques integrate electrical and mechanical functions into a single element using microfabrication technology. A MEMS element is disposed on a chip and covered by a shield or packaged with an underfill adhesive so as to form a MEMS package structure. FIGS. 1A to 1F are cross-sectional views showing different package structures with a MEMS element.[0005]FIG. 1A shows a package structure disclosed by U.S. Pat. No. 6,809,412. Referring to FIG. 1A, the package structure comprises a substrate 10, a chip 14 disposed on the substrate 10 and having a MEMS element 141, a plurality of bonding wires 11 electrically connecting the substrate 10 and the chip 14, and a lid 12 disposed on the ...

AI Technical Summary

Benefits of technology

[0018]According to the present invention, the package structure having at least a Micro Electro Mechanical System (MEMS) element is provided directly on a wafer without the need of a carrier, thus reducing the thickness of the overall structure. Further, the position of the bumps is not limited to the top of the lid. Instead, the bumps are disposed at any positions of the top surface of the package structure. Furthermore, the lid is connected to a ground end through the sub-bonding wires and the metallic traces so as to achieve an EMI shielding effect.

Problems solved by technology

However, the use of the carriers (the substrate 10 of FIG. 1A and the lead frame 10′ of FIG. 1B) increases the thickness of the overall structures and cannot meet the demand for miniaturization.

However, forming the conductive through holes 120 in the lid 12 by drilling incurs high costs.

In addition, misalignment or unstable connection can easily occur to the contact pads 122 which flank the conductive through holes 120, thus leading to poor electrical connection and further adversely affecting the electrical connection quality between the chip 14 and the external electronic element.

However, the above package structure requires a lithography process for forming the traces on the lid, thus incurring high costs.

In addition, the solder balls 16 are confined to the vicinity of the lid to thereby cause solder ball bridge, limit the signal input / output density of the package structure and reduction of the trace spacing, add to the difficulty in attaching the package structure to a circuit board.

As such, the application field of the package structure is limited.

In addition, corresponding to the package structure, a fine pitch circuit board is required, thus increasing the cost.

Further, such a package structure cannot achieve an EMI shielding effect.

Images